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Cooler regions (including Estonia) are expected to be unsuitable for grapevine cultivation due to a short vegetation period and variability of quality parameters regarding insufficient maturation due to variable climatic conditions. Interspecific hybrids (V. vinifera crossings with V. labrusca, V. riparia, V. rupestris, V. lincecumii, V. amurensis) have shown variable frost resistance depending on genotype. In order to improve plant abiotic stress resistance (e.g. temperature effects), different foliar-applied biostimulants and growth regulators have been tested. At the same time, training systems and pruning methods have been investigated in order to affect the vegetative and reproductive characteristics of grapevines, to regulate the yield and subsequently also influence the composition of grape products.
Concerning strawberry fruit quality, nowadays the content of biochemical compounds is with increasing importance to consumers. Strawberry fruits possess a considerable amount of essential nutrients and beneficial phytochemicals, which may have relevant biological activity in human health. However, metabolomic analyses have revealed significant changes in primary metabolites between strawberry cultivars grown under different conditions and using various cultivation techniques.
In the present thesis, the effect of cultivar properties, foliar treatments with glycine-betaine, and different pruning methods and times on hybrid grapevine fruit maturity and quality parameters; as well as the influence of application of humic substances and post-harvest flame-defoliation on strawberry taste-related parameters and antioxidants were investigated and discussed. The main aim of was to find out of the effects of cultivation techniques on the biochemical composition of two different horticultural crops. On one hand, grapevine as a woody plant, and on the other hand, strawberry as an herbaceous plant were investigated.
Grapevine cultivars were selected for the experiments based on the list of recommended cultivars which are already widely cultivated in Estonian climatic conditions as well. Cultivar properties significantly affected the fruit composition and quality of hybrid grapevine cultivars under investigation, but not all the cultivars achieved the sufficient maturity requirements in Estonian climatic conditions. Foliar treatments of glycine-betaine had a significant effect on the quality parameters of interspecific hybrid cultivar ’Rondo’, while earlier-fruiting ’Hasanski Sladki’ showed better results for fruit technological maturity despite the treatments. Spring cane pruning increased the content of soluble solids, total phenolics and anthocyanins, while the maturity parameters did not reach recommended level in case of spring spur pruning.
Post-planting application of humic substances affected significantly the fruit biochemical composition of strawberry cultivar ’Darselect’, though differently according to fruit order (primary, secondary, tertiary). Post-harvest flame-defoliation was suitable using as an organic cultivation technique, but it had significant impact on strawberry plant growth and therefore also on fruit biochemical composition. Defoliation in combination with humic substances had a positive influence on the phenolic compounds in all fruit orders.
In conclusion: quality parameters of grapevine and strawberry were significantly affected by using selected cultivation techniques.